During the last couple of years a huge increase in the number of smart phones, tablet computers and other cellular end user devices has been witnessed. Forecasts predict that by the year 2019 mobile network operators worldwide will have to support more than 8 billion of such devices. Major trends for wireless cellular-based communication systems, such as an increasing number of wirelessly-connected devices as well as their required control information exchange, indicate that the current network signaling solutions will be stretched to their performance limits. Furthermore, the deployment of small cells will also create additional overhead to the network components.
To efficiently support such communication needs, it is required to design new solutions that will offer a considerable overall reduction of signaling messages and avoid bottlenecks of control channels in future cellular networks. One such area that calls for improvement, so as to avoid overloading the network components and the air interface channels, is location management. Location management in cellular systems comprises mainly two processes related to location update and location search/paging. The former is an occasional process during which a mobile device, also referred to as user equipment (UE) herein, sends information related to its current location to the network. For example in 3GPP this process is described in TS23.401. This subsequently leads to a location profile update in a location management server in the network. The profile may include a set of Location Areas (also known as Tracking Areas, TAs) that the UE may reside in without needing to send a new update. This set is commonly referred to as Tracking Area List (TAL). Herein the terms Location Area and Tracking Area are used interchangeably. 3GPP communication systems apply a central policy that assigns a new TAL whose central TA includes the cell where the UE currently resides. This suggests that by making the center of this set of tracking areas close to the UE's current location, the necessity of a UE rapidly making another tracking area update can be reduced. The procedure is initiated by a UE regardless if it is in idle or connected state relative to the cellular network. On the other hand, paging is a process initiated from the network in order to discover the UE when it is in idle state. The paging message according to the 3GPP standard TS36.304 is transmitted across the cells included in all the Tracking Areas that the UE is registered in (which constitute its Tracking Area List). UEs should periodically wake up and listen to the messages transmitted over the Paging Channel (PCH). These messages include the identities of the UEs that are being paged. If the message refers to the UE that listens to the PCH, then the upper layers in the UE trigger a connection establishment, which may be in response to paging. The UE checks if access is barred and if not, the lower layers in the UE perform a contention-based random access procedure.
A signaling trade-off between Tracking Area Update and Paging processes exists. In particular, large Tracking Areas (TA) and/or long Tracking Area Lists (TALs) reduce the number of updates but increase drastically the number of paged cells. On the contrary, small TAs and/or short TALs reduce the number of paged cells but lead to increased number of location updates triggered from the UEs. Hence, it is important to use location management schemes that keep a concise set of location information (i.e., Tracking Areas Lists) for all UEs, while optimizing the signaling overhead for finding the UEs.
Grouping of UEs to clusters is a promising solution in order to support the vast number of UEs in cellular networks. Grouping may be performed based on common behavior among mobile devices e.g., observed moving patterns of UEs or any other characteristic related to the way UEs use services. For example, moving patterns of UEs can be utilized, and the UEs with correlated mobility can be clustered together. As far as location management is concerned, a single member of the group can be assigned with the task to report the location of the whole cluster. Having a representative to report the location of the whole group (hereinafter called cluster rapporteur) can reduce the overall number of location updates.
However, this type of solutions faces some serious shortcomings. An analysis of past historical data, related to moving patterns has to be performed to form a cluster. Although applicable to UEs that present repetitive behavior, they are not suitable for clustering UEs that do not share this attribute (e.g., moving cars). For such cases, the paging accuracy can become even worse than the standard 3GPP process defined in TS36.304, if the page miss ratio increases. This can particularly happen, for example, when the moving pattern of a cluster member becomes different from the moving pattern of the cluster representative, also called cluster header. In this case, these mechanisms have a slow response time, during which the location information for that member that is stored in the network may be incorrect. As a consequence, the network may not be able locate the UE correctly so as to route its incoming calls or data to it, resulting in page miss. Thus, it is difficult to avoid page misses when performing location management for one or multiple users. Moreover, such solutions require that the UEs perform their periodic location update independently if they cross the boundaries of a location area or not.
In a cluster-based method described in U.S. Pat. No. 8,369,876 the decision for altering the Location Management is taken by the network. This includes registering devices to clusters, which is done by the network based on past behavior and selecting a cluster representative. This kind of clustering is restrictive because the past behavior does not necessarily mean that it will be repeated in the future (e.g., it is only valid for cyclic sequences), and in addition, it adds extra computational effort to the network entities so as to register devices to clusters.
A similar approach, which faces the above described drawbacks as well, is disclosed in the article “Group Mobility Management for Large-Scale Machine-to-Machine Mobile Networking”, Huai-Lei Fu, Phone Lin, Hao Yue, Guan-Ming Huang, Chia-Peng Lee, Vehicular Technology, IEEE Transactions, vol. 63, no. 3, pp. 1296, 1305, March 2014.
Thus, there is a need for improved mobile wireless communication devices and methods for communicating with a location management server over a wireless communication network, in particular mobile wireless communication devices and methods for communicating with a location management server over a wireless communication network reducing the signaling overhead in the wireless communication network.